The longest SIM-only contract usually offered by mobile operators is 12 months, but Tesco’s chief marketing officer Simon Groves believes that customers are willing to commit to longer deals if they are offered value for money.

“These data rich deals are available for anyone who is in the market for making savvy mobile choices and are happy with their handset,” he explained. “Our customers told us that they are happy to commit to a deal for a longer period of time if it means they don’t have to worry about looking around for the best deal.”

Mr Groves added that customers opting for a SIM-only deal could save themselves hundreds of pounds a year, as their contract will not include the cost of a new handset.

The two 18-month tariffs being introduced by the retailer are £10 a month for 1,000 minutes, 5,000 texts and 1GB of data and £12.50 a month for 1,500 minutes, 5,000 texts and 2GB of data.

Anyone signing up for the new contracts will also automatically have access to Tesco Mobile’s Anytime Upgrade package. This allows them to upgrade their handset at any point during the 18 month period, without having to pay the remaining time on their contract or any termination fees.

Although Tesco Mobile has 4 million customers and yearly profit figures in excess of £100 million, it may not be much help to its parent company for much longer. Tesco, which last month announced losses of £6.4 billion, is reportedly set to sell its 50 per cent stake in Tesco Mobile in order to reduce company debt.